Topic: declaration through use

topics > computer science > data > Group: type declaration

data type by lexical constraints


The name or the context of a reference can declare its existence. A name used for file operations could implicitly declare the name to be a file. Lexical constraints can declare the type of the variable. This practice was started to give the programmer a wide variety of readily available names, but because typographical errors can easily create a valid but meaningless name, this practice does not exist is most modern programming languages.

An alternative used in Thesa is to pre-define data names for use anywhere in the database. This guarantees that a single name will have a single meaning while at the same time removing the declarative overhead from the programmer. (cbb 5/80)

Subtopic: contextual declaration up

QuoteRef: elcoEW_1971 ;;481 a'=1 defines new variable A with value of 1
QuoteRef: sammJE_1969 ;;575 contextual declaration eg get file (master) data declares mast as type file

Subtopic: default typing up

QuoteRef: simscrip_1971 ;;152 Normally ... for default typing

Subtopic: implicit typing up

Quote: provide implicit typing for initialized type declarations [»dorwSM1_1997]
Quote: implicitly typed local declaration from copy assignment; var keyword [»bierGM10_2007]
Quote: LINQ infers IEnumerable from a select expression; it compiles with a lambda expression [»bierGM10_2007]
Quote: an anonymous type is defined by new(f=v, ...); equivalent types if same property names and value types

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Topic: data type by lexical constraints
(15 items)

Updated barberCB 5/04
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